FUNDAMENTALS OF COMMUNICATION ENGINEERING
1. What do
you mean by radio communication?
Ans. The
process sending audio signal from a source to distant destination using carrier
wave is called radio communication.
2. Explain communication system with the help of
block diagram?
Source
destination
3.Wite name of sub units of radio communication
system?
i. Transmitters
ii. Transmission
Channel
iii. Receiver
4 What do you understand by modulation?
Ans. The
process of varying one of the characteristics of a high frequency wave ai
accordance with the instantaneous value of a low frequency signal is called
modulation.
5 What is modulating wave?
Ans. Low
frequency signal is called modulating wave.
6 What is carrier wave?
Ans. High
frequency wave is called carrier wave.
7 What are different types of modulation?
Ans. i.
Amplitude modulation (AM)
ii. Frequency
Modulation (FM)
iii. Phase
modulation (PM)
8 Give the definition of Amplitude modulation (AM)?
Ans .
Amplitude modulation (AM) is a technique used in electronic communication, most
commonly for transmitting information via a radio carrier wave. AM works by
varying the strength of the transmitted signal in relation to the information
being sent.
9 Give the definition of Frequency Modulation (FM).
Ans.
Frequency modulation (FM) conveys information over a carrier wave by varying
its instantaneous frequency in accordance with the frequency of the carrier
wave.
10 What is modulation index?
Ans.
Modulation index of amplitude modulation is defined as the ratio of the
amplitude of the modulating wave to the amplitude of the carrier wave
11 what are the disadvantages of AM?
i. Smaller
operating range
ii. Poor
audio Quality
iii. Low
Efficiency
iv.Reception
noisy
12 What are the advantages of FM?
Ans.
i. Noiseless
Reception
ii. Better
Quality
iii. High
operating range
iv.Efficiency
is very high
13.
What are
the disadvantages of FM?
Ans. i.
Costly equipments
ii. Smaller
area of reception iii.Much wider channel is required
14.
What is
demodulation?
Ans. The
process of recovering the audio signal from modulated wave is known as
demodulation. Or detection. Thus demodulation is reverse process of modulation
.
15 Give the definition of phase
modulation (PM)?
Ans. In
this he phase of the carrier wave is varied in accordance with the
instantaneous value of modulating signal.
16 What GSM and CDMA stands for?
Ans. GSM
stands for Global system for mobile communication.
CDMA
stands for Code division multiple access.
17 What do you understand by the
term television.
Ans. Television
(TV) is the most widely used telecommunication medium for transmitting and
receiving moving images that are either monochromatic ("black and
white") or color, usually accompanied by sound. "Television" may
also refer specifically to a television set, television programming or
television transmission.
18 Determine the size of antenna
working at frequency of 20 kHz and wave length of wave 1.5*106 m given that
velocity of light to be3*108 m/s .
Ans. λ =
c/f
= 3*108
m/s/20*103 = 15*103 m
Size of
antenna = λ/4 = 3750 m. ans.
19 What is super heterodyne radio receiver ?
Ans. It
is an improved radio receiver which employs the principle of heterodyning
(means frequency translation
20. What is the basic principle of communication
satellites?
Ans. communication
satellites has uplink and down link frequency and used for various research
works and weather forecasting.
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